AArch64: expand G_DIVREM operations in GlobalISel

[t.p.northover]

Summary

We don't have a specific instruction for these, so they should be expanded to whatever separate division & multiplication is needed.

[paquette]

llvm/test/CodeGen/AArch64/GlobalISel/legalize-divrem.mir

2

Minor nit on the run-line

[t.p.northover]

Thanks, committed as ac1647cc80 with the suggested change.

llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp

AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
 
   getActionDefinitionsBuilder({G_SDIV, G_UDIV})
       .legalFor({s32, s64})
       .libcallFor({s128})
       .clampScalar(0, s32, s64)
       .widenScalarToNextPow2(0)
       .scalarize(0);
 
-  getActionDefinitionsBuilder({G_SREM, G_UREM})
+  getActionDefinitionsBuilder({G_SREM, G_UREM, G_SDIVREM, G_UDIVREM})
       .lowerFor({s1, s8, s16, s32, s64});
 
   getActionDefinitionsBuilder({G_SMULO, G_UMULO}).lowerFor({{s64, s1}});
 
   getActionDefinitionsBuilder({G_SMULH, G_UMULH}).legalFor({s32, s64});
 
   getActionDefinitionsBuilder({G_SMIN, G_SMAX, G_UMIN, G_UMAX})
       .lowerIf([=](const LegalityQuery &Q) { return Q.Types[0].isScalar(); });

llvm/test/CodeGen/AArch64/GlobalISel/legalize-divrem.mir

+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -O0 -mtriple=aarch64-- -run-pass=legalizer %s -o - | FileCheck %s
+---
+name:            test_udivrem_64
+body:             |
+  bb.0.entry:
+    ; CHECK-LABEL: name: test_udivrem_64
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $x0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY $x1
+    ; CHECK: [[UDIV:%[0-9]+]]:_(s64) = G_UDIV [[COPY]], [[COPY1]]
+    ; CHECK: [[UDIV1:%[0-9]+]]:_(s64) = G_UDIV [[COPY]], [[COPY1]]
+    ; CHECK: [[MUL:%[0-9]+]]:_(s64) = G_MUL [[UDIV1]], [[COPY1]]
+    ; CHECK: [[SUB:%[0-9]+]]:_(s64) = G_SUB [[COPY]], [[MUL]]
+    ; CHECK: $x0 = COPY [[UDIV]](s64)
+    ; CHECK: $x1 = COPY [[SUB]](s64)
+    %0:_(s64) = COPY $x0
+    %1:_(s64) = COPY $x1
+    %2:_(s64), %3:_(s64) = G_UDIVREM %0, %1
+    $x0 = COPY %2(s64)
+    $x1 = COPY %3(s64)
+
+...
+---
+name:            test_sdivrem_32
+body:             |
+  bb.0.entry:
+    ; CHECK-LABEL: name: test_sdivrem_32
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $x0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY $x1
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[COPY]](s64)
+    ; CHECK: [[TRUNC1:%[0-9]+]]:_(s32) = G_TRUNC [[COPY1]](s64)
+    ; CHECK: [[SDIV:%[0-9]+]]:_(s32) = G_SDIV [[TRUNC]], [[TRUNC1]]
+    ; CHECK: [[SDIV1:%[0-9]+]]:_(s32) = G_SDIV [[TRUNC]], [[TRUNC1]]
+    ; CHECK: [[MUL:%[0-9]+]]:_(s32) = G_MUL [[SDIV1]], [[TRUNC1]]
+    ; CHECK: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[TRUNC]], [[MUL]]
+    ; CHECK: $w0 = COPY [[SDIV]](s32)
+    ; CHECK: $w1 = COPY [[SUB]](s32)
+    %0:_(s64) = COPY $x0
+    %1:_(s64) = COPY $x1
+    %2:_(s32) = G_TRUNC %0(s64)
+    %3:_(s32) = G_TRUNC %1(s64)
+    %4:_(s32), %5:_(s32) = G_SDIVREM %2, %3
+    $w0 = COPY %4(s32)
+    $w1 = COPY %5(s32)
+
+...
+---
+name:            test_sdivrem_8
+body:             |
+  bb.0.entry:
+    ; CHECK-LABEL: name: test_sdivrem_8
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $x0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY $x1
+    ; CHECK: [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[COPY]](s64)
+    ; CHECK: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[TRUNC]], 8
+    ; CHECK: [[TRUNC1:%[0-9]+]]:_(s32) = G_TRUNC [[COPY1]](s64)
+    ; CHECK: [[SEXT_INREG1:%[0-9]+]]:_(s32) = G_SEXT_INREG [[TRUNC1]], 8
+    ; CHECK: [[SDIV:%[0-9]+]]:_(s32) = G_SDIV [[SEXT_INREG]], [[SEXT_INREG1]]
+    ; CHECK: [[TRUNC2:%[0-9]+]]:_(s32) = G_TRUNC [[COPY]](s64)
+    ; CHECK: [[SEXT_INREG2:%[0-9]+]]:_(s32) = G_SEXT_INREG [[TRUNC2]], 8
+    ; CHECK: [[TRUNC3:%[0-9]+]]:_(s32) = G_TRUNC [[COPY1]](s64)
+    ; CHECK: [[SEXT_INREG3:%[0-9]+]]:_(s32) = G_SEXT_INREG [[TRUNC3]], 8
+    ; CHECK: [[SDIV1:%[0-9]+]]:_(s32) = G_SDIV [[SEXT_INREG2]], [[SEXT_INREG3]]
+    ; CHECK: [[COPY2:%[0-9]+]]:_(s32) = COPY [[SDIV1]](s32)
+    ; CHECK: [[TRUNC4:%[0-9]+]]:_(s32) = G_TRUNC [[COPY1]](s64)
+    ; CHECK: [[MUL:%[0-9]+]]:_(s32) = G_MUL [[COPY2]], [[TRUNC4]]
+    ; CHECK: [[TRUNC5:%[0-9]+]]:_(s32) = G_TRUNC [[COPY]](s64)
+    ; CHECK: [[COPY3:%[0-9]+]]:_(s32) = COPY [[MUL]](s32)
+    ; CHECK: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[TRUNC5]], [[COPY3]]
+    ; CHECK: [[COPY4:%[0-9]+]]:_(s32) = COPY [[SDIV]](s32)
+    ; CHECK: [[COPY5:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; CHECK: $w0 = COPY [[COPY4]](s32)
+    ; CHECK: $w1 = COPY [[COPY5]](s32)
+    %0:_(s64) = COPY $x0
+    %1:_(s64) = COPY $x1
+    %2:_(s8) = G_TRUNC %0(s64)
+    %3:_(s8) = G_TRUNC %1(s64)
+    %4:_(s8), %5:_(s8) = G_SDIVREM %2, %3
+    %6:_(s32) = G_ANYEXT %4(s8)
+    %7:_(s32) = G_ANYEXT %5(s8)
+    $w0 = COPY %6(s32)
+    $w1 = COPY %7(s32)
+
+...

llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir

 # DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 #
 # DEBUG-NEXT: G_UREM (opcode {{[0-9]+}}): 1 type index, 0 imm indices
 # DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
 # DEBUG-NEXT: .. the first uncovered type index: 1, OK
 # DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 #
 # DEBUG-NEXT: G_SDIVREM (opcode {{[0-9]+}}): 1 type index, 0 imm indices
-# DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
-# DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
+# DEBUG-NEXT: .. the first uncovered type index: 1, OK
+# DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 #
 # DEBUG-NEXT: G_UDIVREM (opcode {{[0-9]+}}): 1 type index, 0 imm indices
-# DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
-# DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
+# DEBUG-NEXT: .. the first uncovered type index: 1, OK
+# DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 #
 # DEBUG-NEXT: G_AND (opcode {{[0-9]+}}): 1 type index, 0 imm indices
 # DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
 # DEBUG-NEXT: .. the first uncovered type index: 1, OK
 # DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 #
 # DEBUG-NEXT: G_OR (opcode {{[0-9]+}}): 1 type index, 0 imm indices
 # DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}